Manual speed selector of automatic vehicle transmission

ABSTRACT

A manual speed selector of an automatic vehicle transmission in which a line pressure is supplied from a manual valve capable of being changed over a shift lever to control solenoid valves so as to selectively supply hydraulic pressure to frictional engagement devices by shift valves. The shift lever can be moved between an automatic shift mode position and a manual shift mode position, and a transitive position is provided between these two mode positions. At the transitive position, the manual valve is set in a position such as to enable supply of hydraulic pressure, and the transmission can be set in a neutral state by controlling the solenoid valves. If the preceding shift lever position is neutral, the neutral state can be maintained or, when the shift lever is in the transmissive position, the neutral state can be set according to the time for which the shift lever is continuously placed in the transitive position and to the vehicle speed.

BACKGROUND OF THE INVENTION

This invention relates to a manual speed selector of an automaticvehicle transmission whereby the driver can select, by manual operation,a shift stage that he or she wishes to set.

Conventionally, as the shift lever is used to select a running range,e.g., a range D, a range S, and a range L, in an automatic vehicletransmission, a predetermined shift stage is automatically selectedaccording to the vehicle speed and the throttle opening in each range,thereby automatically shifting the transmission. As the shift lever ismoved along an I-shaped straight line pattern, a manual valve linkedthereto in the hydraulic circuit is moved to selectively operatefrictional engagement devices according to the selected range.

However, the shift speed that a driver wishes to select at a givenoperating state will vary according to the driver's individualpreference, and the shift stage automatically selected by the automatictransmission does not always coincide with the shift stage the driverwishes to select. Manual transmissions are advantageous in this respect.

An automatic vehicle transmission has been provided which is arranged toenable manual speed changes and to enable the drive to select a shiftstage (refer to Japanese Patent Laid-Open No. 61-157855).

In the above mentioned prior art transmission, an H-shaped shift patternsimilar to a pattern for manual shifting is formed so as to be connectedto the conventional I-shaped pattern, shift stage positions for manualshifting are set in the H-shaped pattern, and a switch operated by thearrival of the shift lever is provided at each shift stage position.When the shift lever is moved from the I-shaped straight line pattern toone of the positions of the H-shaped pattern, the shift lever isdisconnected from the manual valve of the hydraulic circuit, andfrictional engagement devices are selected and operated by a signalsupplied from the switch provided at the corresponding H-shaped patternpostion to select the corresponding shift stage.

In this type of manual speed selector for automatic vehicletransmissions, however, the shift lever is necessarily passed throughthe D range position in which automatic shifting is effected, when theshift lever is moved from the I-shaped straight line pattern to theH-shaped pattern. However, a problem in that the driver will feel adifference between the shifting operation and the motion of the vehicleis encountered. For example, if the shift lever is moved from a range Nto a first speed position in the H-shaped pattern, the shifttherebetween is effected via a first speed in the range D, that is, thefirst speed is selected after creep-starting. Also, a manual shift forstarting in a second speed must be effected via the first speed in therange D and the driver does not feel good responsiveness to manualshifting. In the case of a shift from, for example, a fourth speed tothe range N, the shift also involves automatic shifting in the range D,and the same problem is encountered.

In this type of manual speed selector for automatic vehicletransmissions, when the shift lever is moved from a certain shift stageselecting position to effect the next shift stage selection, theprevious shift stage is maintained to enable power-on shifting in anintermediate state before a new signal is input. Accordingly, in a casewhere the driver presses the accelerator pedal while believing that thetransmission is in the same state as the neutral of a manualtransmission, there is a risk of a friction member being burnt if theprevious shift stage is the fourth speed stage or a risk of the vehicleabruptly starting if the previous shift stage is the first speed stage.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a manual speedselector for an automatic vehicle transmission capable of enabling thedriver to have a feeling of the shifting that he or she wants at thetime of selection, between a power-on shift and a neutral state, as wellas enabling the transmission to be manually shifted.

To achieve the object, according to the present invention, there isprovided a mechanism having a manual valve positioned by a shift lever,and shift valves controlled by a plurality of solenoid valves, whereinhydraulic pressure is supplied to or is discharged from frictionalengagement devices by changeover of the shift valves to automaticallyshift the transmission.

The shift lever can be moved between an automatic shift mode positionand a manual shift mode position, and a transitive position is providedbetween the automatic shift mode position and the manual shift modeposition. At the transitive position, the manual valve is set in aposition such as to enable supply of hydraulic pressure to thefrictional engagement devices, and a neutral state in which the power ofthe engine is not transmitted to the transmission canbe established bythe control of the plurality of solenoid valves.

According to the present invention, the transitive position is providedfrom which each shift stage can be selected and at which a neutral stateis established. At the transitive position, the manual valve of thehydraulic circuit is in a range DE position but a neutral state isestablished in which the driving power of the engine is not transmittedto the transmission.

In the manual shift mode, therefore, it is possible to effect manualshifting via the neutral transitive state as well as to shift thetranmission manually in a simple manner. A shift range, e.g., a range Nor a range D, or certain shift stage previously selected can thereforebe maintained at the transitive position, thereby eliminating thepossibility of a feeling of the creep starting or shifting of theconventional automatic transmission. The driver can have the appropriatemanual shift feeling that he or she wants.

The manual valve can be set in a position such as to supply hydraulicpressure to the frictional engagement devices and, if the precedingshift lever position is neutral, a neutral state can be set by controlof the plurality of solenoid valves.

According to the present invention, as described above, the selectionfrom the automatic shift mode position to the manual shift mode positionis effected through the transitive position. When the shift lever is inthe transitive position, setting of each shift stage or neutral controlprocessing is performed according to need.

That is, in the transitive position, if the preceding shift leverposition is neutral, the neutral state is maintained until one of theshift stages or the range D is selected, thereby preventing a feeling ofshift state difference. Power-on shifting can also be performed ifnecessary.

In a case where, when the shift lever is set in the transitive position,the vehicle speed is low (or zero) or, where the shift lever is left atthe transitive position for a predetermined time, neutral controlprocessing is performed. This neutral control processing makes ispossible to prevent a friction member from being burnt when theaccelerator pedal is pressed while the transmission is shifted to a highspeed stage during stoppage. It is also possible to prevent creepingduring stoppage. Since the neutral state is established only when thevehicle travels at a low speed or when the shift lever is continuouslyleft in the transitive position for the predetermined time, power-onshifting or neutral can be selected in accordance with the driver'swill.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a perspective view of a shift lever assembly of a manualspeed selector of an automatic vehicle transmission in accordance withthe present invention;

FIG. 2 is a diagram of the mechanical construction of the automaticvehicle transmission of the present invention;

FIG. 3 is a diagram of a hydraulic circuit for controlling the automaticvehicle transmission of the present invention;

FIG. 4 is a diagram of the operation of the automatic vehicletransmission of the present invention;

FIG. 5 is a side view of a manual valve disconnection device;

FIG. 6 is a side view in the direction of the arrow C of FIG. 5;

FIG. 7(a) to 7(h) are diagrams of the operation of the manual valvedisconnection device shown in FIG. 5;

FIG. 7(a) to 7(d) are cross-sectional views taken along the line A--A ofFIG. 5;

FIG. 7(e) to 7(h) are cross-sectional views taken along the line B--B ofFIG. 5;

FIG. 8 is a diagram of the construction of a control unit;

FIG. 9 ia a flow chart of a control process;

FIG. 10 is a flow chart of a shift position discrimination process;

FIG. 11(a) to 11(f) are diagrams of manual shift information; and

FIG. 12 is a flow chart of a neutral control process.

DESCRIPTION OF PREFERRED EMBODIMENT

An embodiment of the present invention will be described below in detailwith reference to the accompanying drawings.

FIG. 2 shows the construction of an automatic vehicle transmission inaccordance with the present invention.

As shown in FIG. 2, a five-speed automatic transmission 21 has a torqueconverter section 22, a four-speed automatic shift gear mechanismsection 23 constituting a main shift gear unit, and an underdrivemechanism section 25 constituting a sub shift gear unit.

The torque converter section 22 has a torque converter 26, and a lock-upclutch 27. The torque of an engine crankshaft 28 is transmitted to aninput shaft 29 through a fluid coupling or by mechanical connection ofthe lock-up clutch 27.

The four-speed shift gear mechanism section 23 has a single planetarygear unit 30 and a dual planetary gear unit 31. In the two planetarygear units 30 and 31, a carrier CR and a sun gear S are intergrallyformed. The input shaft 29 is connected to a ring gear R1 of the singleplanetary gear unit 30 through a first clutch C₁, and is also connectedto the sun gear S through a second clutch C₂.

The sun gear S is directly braked B₁. A second brake B₂ prevents the sungear S from rotating in one direction by means of a first one-way clutchF₁. A ring gear R2 of the dual planetary gear unit 31 is connected tothe input shaft 29 through a third clutch C₀. A third one-way clutch F₀for stopping the sun gear S so that the number of revolutions of the sungear S does not exceed the number of revolutions of the input shaft 29is interposed between the input shaft 29 and the sun gear S. The carrierCR is connected to a counter drive gear 32 which serves as an output forthe four-speed automatic shift gear mechanism section 23.

The underdrive mechanism section 25 has a single planetary gear unit 33.A ring gear R3 of the single planetary gear unit 33 is connected to acounter driven gear 35 in constant engagement with the counter drivegear 32, and a carrier CR3 is connected to an output pinion 36.

Further, a sun gear S3 is prevented by a fourth one-way clutch F₄ fromrotating in one direction and is braked by a fourth brake B₄. The sungear S3 is connected to the carrier CR3 through a fourth clutch C₃. Theoutput pinion 36 is connected to left and right front axles 39r and 39lthrough a differential mechanism 37.

FIG. 3 shows a diagram of a hydraulic circuit for controlling theautomatic vehicle transmission in accordance with the presentinvention..

A hydraulic circuit 40 includes hydraulic servos C0, C1, C2, and C3 forthe clutches shown in FIG. 2, and other hydraulic servos B1, B2, B3 andB4 for the brakes also shown in FIG. 2. The hydraulic circuit 40 alsoincludes a manual valve 10, a spool 10a for movement in the manual valve10 to transmit pressure in each range, a 1-2 shift valve 11 constitutinga first shift valve, a 3-4 shift valve 12 constituting a second shiftvalve, a 2-3 shift valve 13 constituting a third shift valve, a 4-5shift valve 16, and a B3 changeover valve 17.

First to third solenoid valves S₁ to S₃ are also provided. The firstsolenoid valve S₁ serves to control the 1-2 shift valve 11 and the 3-4shift valve 12. The second solenoid valve S₂ serves to control the 2-3shift valve 13, and the third solenoid valve S₃ serves to control the4-5 shift valve 16 and the B3 changeover valve 17.

There are also provided a lock-up control valve 60, a fourth solenoidvalve S₄ for controlling the lock-up control valve 60 with respect tothe duty ratio, and a lock-up modulator valve 61 for stabilizing thefourth solenoid valve S₄.

There are further provided a primary regulator valve 63, a secondaryregulator valve 65, a low modulator valve 69, a cooler 79, a coolerbypass valve 71, a throttle valve 72 for freely controlling hydraulicpressure, operated by a linear solenoid valve S₅, a solenoid modulatorvalve 73, a B1 sequence valve 74, and an accumulator control valve 75.The torque converter 26, the lock-up clutch 27 and a hydraulic pump Pare also connected to this hydraulic circuit.

There are further provided the following pressure regulating valves andaccumulators. Pressure regulating valves 76a, 76b, 76c, and 76d andaccumulators 77a, 77b, 77c, and 77d are provided to operate inassociation with the second brake hydraulic servo B2, the third brakehydraulic servo CO, the fourth clutch hydraulic servo C3, and the firstbrake hydraulic servo B1, respectively. An accumulator 77e is providedfor the first clutch hydraulic servo C1, and an accumulator 77f isprovided for the second clutch hydraulic servo C2. A case mount typeaccumulator 80 is provided which communicates with the fourth brakehydraulic servo B4.

In the five-speed automatic transmission 21 having this construction,the first to fourth solenoid valves S₁ to S₄ of the hydraulic circuit 40are operated according to the range selected by the manual valve 10 toeffect predetermined operations of the clutches C₀ to C₃, the brakes B₁to B₄ and the one-way clutches F₀ to F₃, as shown in the operationdiagram of FIG. 4, thereby setting a range P (parking), a range R(reverse), a range N (neutral), each of first to fifth speeds in a rangeD (forward), a transitive neutral (N), or a manual first speed.

In a range D first speeds state (1st position), the first solenoid valveS₁ is off, i.e., in a supplying state, the second solenoid valve S₂ ison, i.e., in a draining state, and the third solenoid valve S₃ is off,i.e., in a draining state. Accordingly, the 1-2 shift valve 11 and the3-4 shift valve 12 are in upper half positions as viewed in FIG. 3,while the 2-3 shift valve 13, the 4-5 shift valve 16 and the B3changeover valve 17 are in lower half positions as viewed in FIG. 3.

In this state, a line pressure oil passage La and an oil passage Dacommunicate with each other through the manual valve 10, and the linepressure thereof is supplied to the first clutch hydraulic servo C1through an oil passage Db, the 4-5 shift valve 16, and an oil passageDc. The line pressure in the line pressure oil passage La is alsosupplied to the fourth brake hydraulic servo B4 through the 2-3 shiftvalve 13 and a line pressure oil passage Lb. The first clutch C₁ isthereby engaged and the fourth brake B4 is thereby operated in thefive-speed automatic transmission 21.

At this time the torque of the input shaft 29 is transmitted to the ringgear R1 of the single planetary gear unit 30 through the first clutchC₁. At this time also, the rotation of the ring gear R2 of the dualplanetary gear unit 31 is stopped by the second one-way clutch F₂. Thecommon carrier CR therefore rotates in a normal direction at a speedgreatly reduced while rotating the sun gear S in the reverse direction,and the torque of the carrier CR is transmitted from the counter drivegear 32 to the counter driven gear 35 of the underdrive mechanismsection 25. In the underdrive mechanism section 25, the fourth brake B4and the fourth one-way clutch F₃ are operated so that the first speed ofthe whole of the five-speed automatic transmission 21 is obtained by thecooperation of the four-speed automatic shift gear mechanism section 23in the first speed state and the underdrive mechanism section 25.

In the range D second speed state (2nd position), the first solenoidvalve S₁ in the first speed state is turned on and changed over to adraining state. Then the 1-2 shift valve 11 and the 3-4 shift valve 12are changed over to lower half positions so that the line pressure issupplied to the second brake hydraulic servo B2 through the oil passageDa, the 1-2 shift valve 11 and an oil passage Dd. In this state,therefore, the second brake B₂ is operated simultaneously with theengagement of the first clutch C₁.

As the second brake B₂ is operated, the B1 sequence valve 74 is changedover to the upper half position by the hydraulic pressure suppliedthrough an oil passage Dh, so that oil passage Df and Dg communicatewith each other. The first brake hydraulic servo B1 is operated by thepressure supplied through the 3-4 shift valve 12, 1-2 shift valve 11,the oil passage Dh, the 4-5 shift valve 16, and an oil passage Di.

The rotation of the sun gear S is stopped by the operation of the firstone-way clutch F₁ based on the second brake B₂ and by the first brakeB₁. By the torque of the ring gear R1 transmitted from the input shaft29, therefore, the ring gear R2 of the dual planetary gear unit 31 isrotated in the normal direction and the carrier CR is rotated in thenormal direction at a reduced speed. The torque of the carrier CR istransmitted from the counter drive gear 32 to the counter driven gear 35of the underdrive mechanism section 25. The four-speed automatic shiftgear mechanism section 23 in the second speed state and the underdrivemechanism section 25 cooperate to establish the second speed of thefive-speed automatic transmission 21.

In a range D third speed state (3rd position), the second solenoid valveS₂ in the second speed state is turned off and changed over to asupplying state. Then the line pressure in the oil passage Da is appliedto a right control oil chamber of the 2-3 shift valve 13 so that the 2-3shift valve is changed over to the upper half position. The linepressure of the line pressure oil passage La is thereby supplied to thefourth clutch hydraulic servo C3 through the shift valve 13 and a linepressure oil passage Lc. At this time the fourth brake hydraulic servoB4 is set in a drained state. The fourth brake B₄ is thereby releasedand the fourth clutch C3 is thereby engaged to establish a directconnection with the underdrive mechanism section while maintaining thefour-speed automatic shift gear mechanism section 23 in the second speedstate. Consequently, third speed for the five-speed automatictransmission 21 can be obtained by the combination of the four-speedautomatic shift gear mechanism section 23 in the second speed state andthe underdrive mechanism section 25 directly connected to each other.

In a range D fourth speed state (4th position), the first solenoid valveS₁ in the third speed state is turned off and changed over to the supplystate. Then the line pressure is applied to a right control oil chamberof the 3-4 shift valve 12 so that the 3-4 shift valve 12 is changed overto the upper half position. The line pressure is also supplied to aright control oil chamber of the 1-2 shift valve 11. Since the linepressure is previously applied to a left control oil chamber of thisshift valve and since this pressure acts in cooperation with the urgingforce of a spring, the 1-2 shift valve 11 is restrained in the lowerhalf position.

The range D pressure is therefore supplied to the third clutch hydraulicservo CO via the 1-2 shift valve 11, the oil passage Da, the 3-4 shiftvalve 12, and an oil passage Dk. The third clutch C₀ is thereby engagedsimultaneously with the engagement of the first clutch C₁ and the fourthclutch C₃ and the operation of the second brake B₂.

At this time the torque of the input shaft 29 is transmitted to the ringgear R1 of the single planetary gear unit 30 through the first clutch C₁and to the ring gear R2 of the dual planetary gear unit 31 through thethird clutch C₀. Accordingly, the elements of the planetary gear units30 and 31 are integrally rotated to transmit the torque from the carrierCR to the counter drive gear 32 at the same speed as the input shaft 29.A fourth speed output at the same rotational speed as the input shaft 29is obtained through the output pinion 36 by the combination of thetorque of the counter drive gear 32 and direct connection of theunderdrive mechanism section 25.

In a range D fifth speed state (5th position), the solenoid valve S₃ inthe fourth speed state is turned on and changed over to a supply state.Then the 4-5 shift valve 16 is changed over to an upper half position,the first clutch hydraulic servo C1 is drained through a drain port, andthe line pressure is supplied to the first brake hydraulic servo B1through the oil passage Da, the 4-5 shift valve 16 and the oil passageDi, thereby operating the first brake B₁.

At this time, the torque of the input shaft 29 is transmitted to thering gear R2 of the dual planetary gear unit 31 through the third clutchC₀ while the sun gear S is stopped. The carrier CR therefore rotates athigh speed while racing the ring gear R1 of the single planetary gearunit 30 at an increased speed. The high speed torque of the carrier CRis transmitted as an overdrive torque to the counter drive gear 32. Thisoverdrive torque acts in cooperation with the underdrive mechanismsection 25 in the directly connected state to provide the fifth speed ofthe five-speed automatic transmission 21.

The above-described operation is performed in an automatic shift mode.According to the present invention, a predetermined shift stage is setby the combination of on and off states of the above-described solenoidvalves when a manual shift mode signal is received. The first speedstage in a manual shift mode, however, is different from that in theautomatic shift mode while the other shift stages are equal to those inthe automatic shift mode.

That is, during running in the automatic shift mode, the brake for eachone-way clutch is operated for braking at the corresponding shift stageexcept for the first speed stage, thereby preventing engine brakingfailure due to a free state of the one-way clutch. However, if the firstspeed is selected during downhill running, the second one-way clutch F₂is freed and there is no engine braking.

To avoid this problem, when the first speed is selected in the manualshift mode, the third solenoid valve S₃ is turned on and changed over tothe supply state, control pressure is supplied to the B3 changeovervalve 17 through an oil passage Dn, thereby changing over the B3changeover valve 17 to the upper half position. The control pressure isthereby applied to a left control oil chamber of the 3-4 shift valve 12through the oil passages Da and Dp so that the 3-4 shift valve 12 ischanged over to the lower half position. As a result, the line pressureis supplied to the third brake hydraulic servo B3 via the oil passageDa, the B3 changeover valve 17, an oil passage Dq, a low modulator valve69, an oil passage Dr, the 3-4 shift valve 12, an oil passage Ds and the1-2 shift valve 11, thereby operating the third brake B₃ and enablingengine braking.

According to the present invention, a manual shift is not effected viaany D range shift stage in the conventional manner. In other words,manual shift can be effected without shifting through any D range shiftstage. For this manual shift, a neutral state is provided in which thedriving force of the engine is not transmitted to the transmission whilethe manual valve 10 of the hydraulic circuit 40 is in a D rangeposition, as shown at (N) of the operation table of FIG. 4.

That is, the first solenoid valve S₁ is turned on and set in thedraining state, the second solenoid valve S₂ is turned off and set inthe supply state, and the third solenoid valve S₃ is turned on and setin the supply state, so that the 1-2 shift valve 11 and the 3-4 shiftvalve 12 are set in the lower half positions while the 2-3 shift valve13 and the 4-5 shift valve 16 are set in the upper half positions. Theclutches C₀, C₁, and C₂ are thereby released and the neutral state isestablished.

The operation in the range P, R, or N is as shown in FIG. 4, and willnot be described in detail in this specification.

FIG. 1 is a perspective view of a shift lever assembly of a manual speedselector of the automatic vehicle transmission in accordance with thepresent invention.

As shown in FIG. 1, the shift lever assembly 100 has a shift lever 101for changing over the running ranges and the shift stages in accordancewith the driver's will, and a guide plate 102 for guiding the shiftlever 101 longitudinally or laterally.

In the guide plate 102 is formed a guide slit 103 which comprises a slit104 extending in a lateral direction, four slits 105 to 108 eachextending continuously from the slit 104 in an upward longitudinaldirection, and two slits 109 and 110 each extending continuously fromthe slit 104 in an downward longitudinal direction. The shift lever 101can be moved along the guide slit 103. The ranges P, R, and N areassigned to the slit 105, the first speed stage is assigned to the slit106, the third speed stage is assigned to the slit 107, the fifth speedstage and the range D are assigned to the slit 108, the second speedstage is assigned to the slit 109, and the fourth speed stage isassigned to the slit 110.

If the fifth speed stage and the range D are assigned to the slit 108 asin this arrangement, they are discriminated between by anautomatic/manual selection switch (not shown). Alternatively, a slit towhich the range D is independently assigned may be formed below the slit105, or the slit 105 for the ranges P, R, and N may be formed below theslit 108 as a continuation thereof.

Next, a manual valve disconnection device will be described below.

FIG. 5 is a side view of the manual valve disconnection device, FIG. 6is a side view in the direction of the arrow C of FIG. 5, and FIGS. 7(a)to 7(h) are diagrams of the operation of the manual valve disconnectiondevice. FIGS. 7(A) to 7(d) are cross-sectional views taken along theline A--A of FIG. 5, and FIGS. 7(e) to 7(h) are cross-sectional viewstaken along the line B--B of FIG. 5.

Referring to FIG. 5 and 6, a bracket 111 is attached to a valve body inwhich the hydraulic circuit 40 shown in FIG. 3 is accomodated. Aconnection rod 112 connected to the spool 10a of the manual valve 10 isslidably attached to the bracket 111. A fixed shaft 113 is attached tothe bracket 111. A first link member 114 is pivotally and rotatablysupported at its one end on the fixed shaft 113. A second link member115 is rotatably and slidably supported at its one end on the fixedshaft 113. An engaging groove 113a and an engaging step portion 113b areformed on the fixed shaft 113, as shown in FIGS. 7(a).

The other end of the first link member 114 is pivotally and rotatablyattached to one end of the connection rod 112. An engaging piece 117having an engaging hole 116 is formed integrally on an intermediateportion of the first link member 114.

The second link member 115 has a perpendicularly bent shape. A movingshaft 118 parallel to the fixed shaft 113 is slidably inserted into thesecond link member 115, and an engaging rod 119 is inserted in and fixedto a lower portion of the second link member 115. As shown in FIG. 7(a),an engaging groove 118a is formed in the moving shaft 118, and ball 120is fitted between the moving shaft 118 and the fixed shaft 113 in thisgroove.

A third link member 121 is pivotally attached to the moving shaft 118and the engaging rod 119. The shift lever 101 is fixed to the third linkmember 121.

The operation of the thus-constructed manual valve disconnection devicewill be described below with reference to FIG. 7.

When the shift lever 101 is at the position for the range P, R, or Nshown in FIG. 1, the second link member 115 is linked with the movingshaft 118 while being slidable on the fixed shaft 113 because ball 120is fitted in the engaging groove 118a of the moving shaft 118 as shownin FIGS. 7(a) to 7(e), and the engaging rod 119 is fitted in theengaging hole 116 of the first link member 114. In this state, as theshift lever 101 is moved to the position P, R and N as shown in FIG. 5,the connection rod 112 is moved by the rotation of the shift lever 101through the third link member 121, the engaging rod 119 and the firstlink member 114, so that the spool 10a of the manual valve 10 shown inFIG. 3 is set in the position corresponding to each range.

When the shift lever 101 is further moved from the position N to theposition of the slit 104 in the longitudinal direction as shown FIG. 1,the spool 10a of the manual valve 10 is set to the positioncorresponding to the automatic shifting range D.

As the shift lever 101 is laterally moved from this position along theslit 104, the second link member 115 and the moving shaft 118 are movedtogether to the right as shown in FIGS. 7(b) to 7(f) since the ball 120is fitted in the engaging groove 118a of the moving shaft 118, and theengaging rod 119 is disengaged from the engaging hole 116 of the firstlink member 114. In this state, the spool 10a of the manual valve 10 ismaintained in the position corresponding to the automatic shifting rangeD. As the shift lever 101 is further moved laterally along the slit 104,the second link 115 is brought into abutment with the engaging stepportion 113b of the fixed shaft 113. At this position, the shift lever101 can be moved into the slit 106 or 109 shown in FIG. 1 to be set inposition corresponding to the first speed or second speed stage.

If the shift lever 101 is further moved laterally along the slit 104,the ball 120 is fitted in the engaging groove 113a of the fixed shaft113 and only the moving shaft 118 is moved to the right to a positionshown in FIGS. 7(c) and 7(g), since the second link member 115 is fixed.At this position, the shift lever 101 can be moved into the slit 107 or110 shown in FIG. 1 to be set in the position corresponding to the thirdor fourth speed stage. If the shift lever 101 is further moved laterallyalong the slit 104, only the moving shaft 118 is moved to the right to aposition shown in FIG. 7(d) and 7(h). At this position, the shift lever101 can be moved into the slit 108 shown in FIG. 1 to be set in theposition corresponding to the range D or the fifth speed stage.

Thus, when in the manual valve disconnection device the shift lever ismoved from the position N shown in FIG. 1 to the lateral slit 104, themanual valve 10 is in the position corresponding to the range D, but thestate (N) of the range D shown in FIG. 4, i.e., a neutral state in whichthe power of the engine is not transmitted to the transmission isprovided by controlling the solenoid valves S₁ to S₃.

In this specification of the present invention, the position of theshift lever 101 to which the shift lever 101 is moved from position N tothe slit 104 as shown in FIG. 1 and in which the shift lever 101 is notset in any of the shift stage positions is defined as the "transitiveposition".

The control of the manual speed selector of the automatic vehicletransmission in accordance with the present invention will now bedescribed below with reference to FIGS. 8 to 12.

FIG. 8 is a diagram of the construction of a control unit, FIG. 9 is aflow chart of a control process, FIG. 10 is a flow chart of a shiftposition discrimination process, FIGS. 11(a) to 11(f) are diagrams ofmanual shift information, and FIG. 12 is a flow chart of a neutralcontrol process.

Referring to FIG. 8, various sensors: a T/M input revolution sensor 201for detecting input speed of revolution of the automatic transmission, avehicle speed sensor 202, a throttle opening sensor 203, and shiftposition sensors 204 are provided. The shift position sensors 204 serveto detect the positions of the shift lever 101 by being provided at theshift lever positions, i.e., a sensor in the slit 105 corresponding tothe range P, R, or N, a sensor in the slit 106 corresponding to thefirst speed stage, a sensor in the slit 107 corresponding to the thirdspeed stage, a sensor in the slit 108 corresponding to the fifth speedstage or the range D, a sensor in the slit 109 corresponding to thesecond speed stage, and a sensor in the slit 110 corresponding to thefourth speed stage. A manual selection switch 205 is also provided whichis turned on if the driver wishes to perform manual shifting. The manualselection switch 205 is not necessary if the range D position isprovided independently as described above with reference to FIG. 1.

Detection signals output from these sensors and switch are input into anelectronic controller 206 and are processed by this controller by beingcompared with various categories of stored date and being descriminatedbased on a program. The electronic controller 206 then outputs signalsto the transmission solenoid valves S₁ to S₃, the fourth solenoid valveS₄ for the lock-up clutch, the linear solenoid valve S₅ for hydraulicpressure control, and a display 207.

FIG. 9 is a flow chart of data processing in the electronic controller206.

In step 211, initialization of a RAM area, an I/O port, a timer, acounter and so on is effected.

In step 212, the vehicle speed and the rotational speed of input of theautomatic transmission are calculated.

In step 213, the states of the shift position sensor 204 and the manualselection switch 205 are detected.

In step 214, a shift position discrimination process is conducted.

This process will be described below with reference to FIG. 10.

In step 301, determination is made as to whether or not the position ofthe shift lever 101 corresponds to the range P, R, or N. If YES, theprocess proceeds to step 302 or, if NO, the process proceeds to step303.

In step 302, an automatic shifting mode flag is set.

In step 303, determination is made as to whether or not the range D isselected. If the range D is selected, the process proceeds to step 304.

In step 304, determination is made as to whether or not the manualselection switch 205 is on. If YES, the process proceeds to step 305 or,if NO, the process returns to step 302.

If the range D position is provided independently as described abovewith reference to FIG. 1, step 304 is unnecessary.

Step 305 and subsequent steps are provided for manual shift modeprocessing.

In step 305, determination is made as to whether or not the position ofthe shift lever 101 corresponds to the fifth speed. If NO, the processproceeds to step 308 or, if YES, the process proceeds to step 306.

In step 306, a shift diagram MSL=5 shown in FIG. 11(a) and a lock-updiagram shown in FIG. 11(f) are selected as shift information MSL.

In step 307, a manual shift mode flag is set.

In subsequent steps 308 to 315, determination of fourth speed, thirdspeed, second speed and first speed is effected in the same manner,shift diagrams MSL=3, 2, 1 shown in FIG. 11(b) to 11(e) and the lock-updiagrams shown in FIG. 11(f) are selected as shift information MSL, anda manual mode flag is set in step 307.

According to the manual shift information shown in FIGS. 11, the timingof engagement of the lock-up clutch is advanced to enable rapid shiftingas shown in FIG. 11(f), while shifting can be effected smoothlyaccording to well-known automatic shift information. Also, as shown inFIGS. 11(a) to (e), a shift-down range is provided with respect to eachshift diagram to prevent the engine from overrunning if the transmissionis shifted from the fifth speed to the first speed, for example.

If the first speed is not selected in step 314, the shift lever 101 isin the position to which it is laterally moved from the position N shownin FIG. 1 to the slit 104 and in which it is set in no shift stage, thatis, the shift lever 101 is in the transitive position. In this case,determination is made again in step 317 as to whether or not the shiftlever 101 is in the transitive position (N). If NO, it is determinedthat a failure has occurred, and failure detection processing of step318 is conducted. If the shift lever 101 is in the transitive position,the neutral control process of step 316 is conducted.

This process will be described below with reference to FIG. 12.

In step 323, determination is made as to whether or not the shiftposition selected immediately previously is neutral, i.e., the positioncorresponding to the range N. If YES, the process proceeds to step 329and shift information MSL is set in N. If NO, the process proceeds tostep 324.

In step 324, determination is made as to whether or not the timer hasbeen started. If YES, the process proceeds to step 326 or, if NO, theprocess proceeds to step 325 to start the timer.

In step 326, determination is made as to whether or not the timermeasurement time is longer than a set time T₁. If NO, the mainprocessing is repeated or, if YES, the process proceeds to step 327.

In step 327, determination is made as to whether or not the vehiclespeed is smaller than a set V. If NO, the main processing is repeatedor, if the vehicle speed is smaller than the set speed, the processproceeds to steps 328 and 329.

In steps 328 and 329, the timer is stopped and shift information MSL isset in N.

After setting the shift information MSL to N, the state N in the range Dshown in the operation table of FIG. 4 is established by controlling thesolenoid valves S₁ to S₃ in a later-described step 222 to prepare toestablish the neutral state in which the power of the engine is nottransmitted to the transmission. In a case where the shift lever 101 isin the transitive position for a short period within the set time, thereis no need for establishing the neutral state, and the preceding shiftinformation MSL is set as the present shift information MSL.

As mentioned above, determination is made in step 327 as to whether ornot the vehicle speed is higher than the set speed V. Alternatively,determination may be made as to whether or not the throttle opening islarger than a set value or as to whether or not a brake signal isdetected.

Subsequent processing will be described below by referring back to FIG.9.

In step 215, the throttle opening (%) and eight throttle steps arecalculated.

In step 216, in the case of automatic shift mode, shift information MSLincluding the well-known shift diagrams and the lock-up diagrampreviously stored is prepared or, in the case of manual shift mode,shift information MSL including the shift diagram and the lock-updiagram according to each shift stage selected in step 214 is prepared,and a shift and engagement of the lock-up clutch are determined from thevehicle speed already calculated and the throttle opening.

In step 217, the timing from shift determination to shift commanding atthe time of shifting, the lock-up engagement timing and the linepressure control timing are set. In this case also, these timings aredifferentiated with respect to the automatic and manual shift modes sothat the transmission is smoothly shifted in the automatic shift mode oris rapidly shifted in the manual shift mode.

In step 218, on/off duty control of the lock-up clutch is effected.

In step 219, detection of short-circuit failure or open failure of thefourth solenoid valve S₄ for lock-up from the output from this solenoidvalve and the input to the monitor circuit is effected.

In step 220, the line pressure control at the time of shifting iseffected with the hydraulic control linear solenoid valve S₅ by theshifting line pressure control timing determined in step 217.

In step 221, detection of short-circuit failure or open failure of eachof the solenoid valves S₁, S₂, and S₃ from the output from that solenoidvalve and the input to the monitor circuit is effected.

In step 222, the solenoid valves S₁, S₂, and S₃ are operated inaccordance with the shift determination of step 216 and the shift timingdetermination of step 217.

In step 223, detection of a failure of the hydraulic control linearsolenoid valve S₅ from the input to the output monitor circuit iseffected.

In step 224, a current corresponding to the necessary line pressuredetermined from the present gear ratio and the throttle opening issupplied to the hydraulic control linear solenoid valve S₅.

In step 225, the transmission gear ratio is calculated from the inputrotational speed and the vehicle speed and is compared with the gearratios corresponding to the first to fifth speeds, and the start and theend of shifting of the transmission are detected.

In steps 226 and 227, the state of the transmission is displayed on thedisplay unit.

It should be understood that the foregoing relates to only a preferredembodiment of the invention, and that the claims are intended to coverall changes and modifications of the example of the invention hereinchosen for the purposes of the disclosure, which do not constitutedepartures from the spirit and scope of the invention.

What we claim is:
 1. A manual speed selector for an automatictransmission for a vehicle having a plurality of frictional engagementelements and a torque converter, said automatic transmission providing amanual mode and an automatic mode of operation, said manual speedselector comprising:(a) shift lever means for providing:(i) an automaticshift mode position in the form of a first pattern of shift positions;(ii) a manual shift mode position in the form of a second pattern ofshift positions; and (iii) a transitive position connecting said firstand second patterns of shift positions. and including a shift lever formanual selection of a shift position in one of said patterns; (b) ahydraulic control system including:(i) a manual valve linked to saidshift lever at least in said automatic shift mode position, for movementresponsive to movement of said shift lever; (ii) a plurality of shiftingsolenoid valves turned on or off responsive to the selection of a shiftposition; (iii) a plurality of shift valves, operated by said solenoidvalves, for selectively transmitting hydraulic pressure to at least onefrictional engagement element to establish a shift state; and (iv) asource of hydraulic pressure in hydraulic communication with thefrictional engagement elements through said shift valves; (c) means forconnecting said hydraulic pressure source to at least one of thefrictional engagement elements, through said manual valve, when saidshift lever is placed in said transitive position; and (d) an electroniccontroller including transition control means for determining if aneutral state should be established responsive to placement of the shiftlever in the transitive position and for controlling operation of saidsolenoid valves, in accordance with that determination, to establish aneutral state in which the power of the vehicle engine is nottransmitted to the transmission, wherein said transition control meanscomprises a timer for measuring the elapsed time said shift leverremains in said transitive position and first comparing means forcomparing said elapsed time with a predetermined time, whereby saidcontroller establishes said neutral state only when said elapsed timeexceeds said predetermined time.
 2. The manual speed selector of claim 1wherein said transitive position sets said manual valve in position forestablishing forward travel responsive to selection of the automaticmode.
 3. The manual speed selector of claim 1 wherein said transitivecontrol means further comprises a sensor for detecting a low speedstate, whereby said controller establishes said neutral state only whensaid low speed state is detected.
 4. The manual speed selector of claim3, wherein said detected low speed state is a detected vehicle speedless than a predetermined vehicle speed.
 5. The manual speed selector ofclaim 3, wherein said detected low speed state is a detected throttleopening less than a predetermined throttle opening.
 6. The manual speedselector of claim 1 wherein said first pattern of shift positionsincludes a neutral position and wherein said transition control meansmaintains a neutral state in said transitive position when the nextpreceding shift lever position was said neutral position.
 7. The manualspeed selector of claim 6 wherein said transitive control means furthercomprises a sensor for detecting a low speed state, whereby saidcontroller establishes said neutral state only when said low speed stateis detected.
 8. The manual speed selector of claim 7, wherein saiddetected low speed state is a detected vehicle speed less than apredetermined vehicle speed.
 9. The manual speed selector of claim 7,wherein said detected low speed state is a detected throttle openingless than a predetermined throttle opening.
 10. The manual speedselector of claim 6 wherein said torque converter has a lock-up clutch.11. The manual speed selector of claim 6 wherein said transitiveposition sets said manual valve in position for establishing forwardtravel responsive to selection of the automatic mode.
 12. The manualspeed selector of claim 6 wherein said torque converter has a lock-upclutch.